1. Field of the Invention
The present invention relates to a wearable display apparatus, and more particularly, to a wearable display apparatus configured for interpupillary distances, allowing left and right image display positions to be adjusted for a user's interpupillary distance.
2. Description of the Related Art
A wearable display apparatus is worn near a user's eyes for viewing images. The wearable display apparatus is widely spread in use due to advantages of being individually wearable, small in size, and providing views of a wide visual angle. Generally, a head mount display (HMD) apparatus, and a spectacles-type display apparatus are types of wearable display apparatuses. The wearable display apparatus is magnified by an optical system and shows a user images displayed on a display device such as an LCD or a CRT. The wearable display apparatus requires very precise optical devices to focus at short distances and avoid eye fatigue since an image screen of the wearable display apparatus is disposed at a position close to the eyes.
Particularly, in view of eyes which are visual subjects, the HMD apparatus is classified into a monocular type and a binocular type. Further, in view of images which are visual objects, the HMD apparatus is classified into a monoscopic type and a stereoscopic type. Of the above, the binocular type is widely used.
For left and right images displayed in the HMD apparatus of the binocular type to be naturally overlapped and recognized by a user, a distance between focusing lenses of the HMD may be adjusted for the interpupillary distance (IPD) of the user. The IPDs of most adult males and females range from 50 mm to 74 mm. Further, some people have different heights in their left and right eyes. If a user wears a binocular HMD differently adjusted from his or her own IPD, left and right images are initially viewed as separated. Also, the images are overlapped in one image by the visual control mechanism of a human being, thereby increasing eye fatigue more than in the case that the IPD of the HMD is adjusted to fit the user's IPD. Accordingly, a method has been disclosed in WO95/10106 by Vertula Vision Inc., in which an optical mechanism is mechanically adjusted to focus left and right images according to a user's diverse interpupillary distances.
FIG. 1 is a view showing a conventional wearable display apparatus.
Referring now to FIG. 1, the conventional HMD includes two display devices 11 and 12, plural mirrors 13, 14, and 15, a beam splitter 16, and focus lenses 17 and 18.
The display devices 11 and 12 display images to be projected to the left and right eyes 20 and 22 of a user.
The focus lenses 17 and 18 are disposed in front of the eyes 20 and 22 of the user, and magnify the images displayed on the display devices 11 and 12 so that the magnified images are provided for the user's eyes.
The plural mirrors 13, 14, and 15 and the beam splitter 16 are used to transform projection paths of the images displayed on the display devices 11 and 12 to the positions of the left and right eyes.
The image displayed on the display devices 11 and 12 are viewed by the user's left and right eyes 20 and 22 via the beam splitter 16, mirrors 13, 14, and 15, and focus lenses 17 and 18. The images projected to the left and right eyes 20 and 22 through the right focus lens 17 and the left focus lens 18 are mutually superimposed and the user recognizes the images as one image.
However, the conventional binocular HMD has a drawback in that the IPD is fixed to an average IPD of users, or the optical system of the HMO has to be mechanically adjusted according to an IPD of the particular user. Thus, for example, the structure of the HMD becomes complicated and the head set becomes heavy in weight.